What I mean by this, should a user run the 4 sensors in the runners along with the one 18"+ down from the turbo like normal, would you be able to tune off the normal wide band, and monitor for per cylinder changes on the other 4?

I'm not sure but I'm gonna go out on a limb and say no. The one in you DP would give you consistent results but the others would be varying based on EGBP which will not be constant based on engine load, boost, state of turbo spool, etc so you wouldn't be able to get any consisted correlation between the DP and the header mounted O2 sensors readings without knowing the pressure in the header at that instant.